Package preforming apparatus



Feb; 1, 1966 R, J. BRowN 3,232,024

PACKAGE PREFORMING APPARATUS Filed May 14, 1962 '7 Sheets-Sheet 1 Feb. 1, 1966 R. J. BRQWN PACKAGE PREFORMING APPARATUS Filed May 14, 1962 7 Sheets-Sheet 2 Feb. 1, 1966 R. J. BROWN PACKAGE PREFORMING APPARATUS 7 Sheets-Sheet 5 Filed May 14, 1962 Feb. 1, 1966 ow 3,232,024

PACKAGE PREFORMING APPARATUS Filed May 14. 1962 7 Sheets-Sheet 4 /50 If H241 m] 120 2 m 1/6 m m 1 Feb. 1, 1966 R. J. BROWN PACKAGE PREFORMING APPARATUS '7 Sheets-Sheet 5 Filed May 14, 1962 Feb. 1, 1966 R. J. BROWN PACKAGE PREFORMING APPARATUS 7 Sheets-Sheet 6 Filed May 14, 1962 Feb. 1, 1966 R. J. BROWN PACKAGE PREFORMING APPARATUS 7 Sheets-Sheet 7 Filed May 14, 1962 .2 l I- E155 Q @E? lllll t:- 1 y,

United States Patent I The present invention relates to structure, means and apparatus for preforming a package having a therm0 stretchablefihn carried within a Cardboard frame so that the film will assume the shape of the goods to be packaged. The typical stretchable film package comprises a die cut card having Windowed therein a thin film of clear plastic material which is thermoplastic so that it is boththermostretchable andthermo-sealable at elevated temperatures.-

Generally, the card is foldable either within or without the windowed area so as toform a surrounding container for the goods placed therein. .Thewindowed area carrying a'stretchable filmis usually preformed to the general contour of the goods to be carried within the card. Thereupon the goods are placed .within the open formed window of the die cut card, th'e'card is. folded over on itself to complete the package and the package is subjected to heat and pressure at least for sealing the thermoplastic film to itself. r I

In the ideal package of this type, the windowed film is stretched thin and tight against the packaged article so as, to appear substantially invisible to a viewer at an ordinary distance. To effect this purpose, it is generally necessary to employ a film having a memory which will tend always to re-form to its initial state of manufacture. Inasmuch as the initial state of manufacture is a flat state, this type of film, when deformed, will attempt to reform itself to the fiat state. This characteristic, while desired, necessarily mean that it is difiicult to cause the filmto as some with permanence any position other than that of its initial state. The length of time that the film will remain in its transient preformed shapewill depend on the film material and on the ambient conditions encountered during the preforming and the storage. Materials presently contemplated as being suitable for skin packaging are polyvinyl chloride, polypropylene, polyacetate, polyethylene and oriented styrene, in addition to other. films. It is desirable for many purposes to provide a preformed card that will retain its shape under a number of ambient conditions and which may betransported to a new location prior to being filled, closed and sealed, j

Therefore, it is an object of this inventionto provide new and improved apparatus for preforming a skin package.

It is a further object of this invention toprovide new and improved apparatus for preforrning the" windowed die cut card so as to establish within the preformed window a set against easy restoration of its memory.

It is also an object of the invention to provide a novel conveying apparatus. p 1

Another object of the invention isa conveying apparatus which clampingly hold the objects.

Further objects and features of the invention pertain to the particular structure and arrangements whereby the above-identified and additional objects of the invention are obtained. i

The invention, both as to its structure and method of usage, will be betterunderstood by reference to the following specification and drawings forming a part thereof wherein:

FIGURE 1 is a perspective view illustrating one embodiment of the package, including the article to be packaged thereby;

FIGURES 2 through 5 are perspective views of the package illustrated in FIGURE 1 during various stages of the formation thereof;

FIGURE 6 is a partial cross-sectional view of the package illustrated in FIGURE 1, including the article to be packaged thereby;

FIGURE 7 is a plan view of one embodiment of the inventive apparatus for preforming the package;

' FIGURE 8 is a front elevational view of the embodiment of the invention illustrated in FIGURE 7;

FIGURE 9 is a side elevational view of the embodiment of the invention illustrated in FIGURE 7;

FIGURE 10 is an enlarged partially cut-away view of a portion of FIGURE 9, illustrating one position of the apparatus;

FIGURE 11 is an enlarged partially cut-away view of a portion of FIGURE 9 illustrating another position of the apparatus;

FIGURE 12 is an enlarged view of a portion of FIG- URE 9 including illustrations in phantom indicating different positions assumed by the disclosed clamping device;

FIGURE 13 is a partially cut-away enlarged view of FIGURE 8 specifically illustrating the front elevational view of the disclosed clamping devices;

FIGURE 14 is a plan view of the disclosed clamping device;

FIGURE 15 is a partially cut-away plan view of the clamping device illustrated in FIGURE 14; and

FIGURE 16 is a bottom plan view illustrating the clamping device illustrated in FIGURE 14.

FIGURES 1 -6 illustrate a package 10 having an article 11 enclosed therein. Package 10 is formed from a windowed card 16 which comprises a die cut board 12 having an aperture 14 which is windowed by a thermoplastic thermo-sealable film 13. The film is of a type which may be deformed and may later be actived to return to its original state. The windowed card 16 becomes preformed. card 20 by deforming the film 13 into article receiving pods 21 and 22 which are dimensioned to receive the article 11 as shown in FIGURES 3 and 4. The card 20 is filled by placing article 11 therein, and closed by folding alonglines 24 causing portions of film 13 to come into face-to-face contact for subsequent heat sealing. The

film may then be activated to return to its original flat state causing it to tightly encase article 11.

Referring now to FIGURES 7 through 16, there is illustrated therein one embodiment of the inventive apparatus. This apparatus prefer-ms a plastic film windowed die cut card 16', similar to card 16 illustrated in FIGURE 3, to the shape of the article to be packaged so that the card may subsequently receive and pack-age such article. In the present illustration, the article to be packaged is a decantershaped bottle. Therefore, aperture 14 of card 16" is formed in the shape of a decanter-shaped bottle, and the film 13' will be preformed in the shape of a decanter-shaped bottle.

Briefly, the disclosed apparatus comprises a continuous conveyor onto which the cards 16' to be preformed are loaded. The conveyor advances the flat card 16' through the varioussteps of formation and finally deposits the preformed card 20 into the provided receptacle. The card 16' is sequentially moved through a plurality of heating stages before the plastic material mounted thereon reaches its thermoplastic temperature range andis ready to be preformed, and subsequently thereto the card 16 is moved into operable relationship with the provided molding apparatus wherein the heated plastic is drawn into the mold to assume the shape of the article to be subsequently skinpackaged. The molding apparatus is withdrawn from While positioned Within the clamps 108the card 16 *is secured against movement. ."As the sprocket chains 110 are driven to their next position the roller bearing portions 124 and, hence, the lever arm 122 of the clamps 108 are moved free of the camming surfaces "144 and the springs 128 of the clamps 108 biases the clamping heads 116 to their closed position to thereby exert a clamping *force'on the card 16' as may be seen in FIGURES 12 and 14.

The sprocket chains 110 are moved to the next station or position 2, as best illustrated in FIGURE 7, and the clamps 108 and hence the card 16' enters the heating stages of the preforming apparatus. The heat is supplied to the card 16 during the heating stages at positions 2, 3, 4 and 5, as illustrated in FIGURE 7, by a plurality of coils positioned within the housing 166. The coils positioned within the housing 166 are 'not illustrated inas much as they vary in both positioning and heat output with the cards 16', i.e., the type of plasticm ate rial, the thickness thereof, the length and width of the aperture, etc. The heating coils can be readily designed when a specific heating problem is presented. The housing 166 for theheatingcoils is attached to a plurality of rollers 168 by suitable brackets 169. The plurality of rollers 168 are positioned to beengageablewith'a pair of'tracks 170, as best seen in FIGURE 9. The tracks 1-70 are mounted on the frame 100by plurality of suitable brackets 172. Therefore, the heating coils positioned within the housing 166 are-readily positioned over the cards 16' and may be moved back past the supporting frame'100 when notin use, as can be seen in FIGURE 7. Attached to the supporting frame 100-i s aninsulatin'g pan174 having positioned therein 'a heat insulating material 176 such as asbestos. The insulating pan 174is provided to insure that no one is accidentally burned afterthe housing 166 and the coils therein have beenmoved past the supporting frame 100. i

The'card 16' is sequentially passed through the heating stages 2, 3, 4 and Stonable'the film tobe in a pliable condition and'to be at a temperature susceptible for preforming. After leaving stage '5, the card 16' is ready'to be preformed and is moved into position 6 directly over the female mold 178. Positioned directly over'the female.

mo1d178 is the cardpositioning'bar 179, as can be seen in FIGURES 7 through 11. Ba'r179 is rigidly attached 'to the frame 100'andbar 179 serves the function of insuring that card 16 is hel d tightly against the female mold 178whe n the female mold 178 engages the card 16'.

The female' mold 178, as best illustrated in FIGURES 8 through 11, has formed therein two pods .180 and 183 which correspond each to one-half of the article to be finally skin-packaged. The contour of the pods 180 and l83 correspond to the contour of the windowed aperture 13' in the card 16 to be preformed. It is essential to quality production that the card 16 be exactly and precisely positionedover the'po'ds lsflzand 183 of the mold 178. This is accomplished partially by the positive mechanicaldrive provided, whichreduces any possibility 6 chamber 186 of the female mold 178. The inner chamber 186 of the female mold 178 is connected to a plurality of smaller channels 188 as best illustrated in FIGURES l1 and 12. The plurality of channels 188 are connected to the pods 180 and 183 through the bottom surfacethereof to insure a uniform vacuum force through pods 180 and 183 at spaced sections therealong. The female mold 178 is removable from the shaft 240 and may be secured thereto by any convenient means. The shaft 240 is securely positioned in the center plane intermediate the plurality of sprocket hubs at both the loading and the discharging end of the preforming apparatus. Therefore, when the length of the card 16' is adjusted for by turning the length adjusting handle 156 the pair of sprocket hubs 142 and the pair of sprocket hubs 1326 move in unison toward and away from each other, leaving the shaft 245) positioned in the aforedescribed center plane regardless of the length of slipping such as would occur with a frictional belt drive. The depth o'fthe pods180 and 183'corresponds tonne-half of the depth of the article to befinally packaged at each cross-sectional plane except for a narrow portion 181 which separates the two pods180 and 183 and insures theproper forming of what will be the bottom of the skin-packaged assembly.

The female mold 178 is connected to ashaft 240 and adjustment.

As the card '16 to be preformed moves into position 6 the shaft 248 moves in'a vertical direction toward the card 16 ascan be seen in FIGURE 10 and when the card 16' reaches the position 6 the mold 178 will be contiguous with the under side thereof as best seen in FIGURE 11 and the bar 179 will be contiguous with the upper side thereof. A vacuum is applied through hose 182 from a vacuum source (not shown) and the air is withdrawn from the under side of the plastic film 13. The air is withdrawn from pod halves 180 and 183 through the plurality of channels 188 interconnecting the pod halves 180 and 183 and the chamber 186, through the threaded coupling 184, the hose 182 and to the vacuum source. The plastic film 13' will then collapse and adhere to the inner surface of the pod halves 181) of the female mold 178.

The plastic film 13' has been heated to a state'in which it is readily stretched and formed by the heating process described. The mold 178 and the cooperating vacuum source applied through the previously described channels serve to partially chillthe plastic film 13 which results in the film acquiring a set or, in other terms, causing the plastic film 13' to remain in its stretched or preformed condition.

'During withdrawal of the mold'178 from the preformed plastic film 13 the vacuum source (not shown) is removed from the hose 182 and blow-off air is allowed to enter the line 182 and consequently the pod halves 180 and 183. Theblow-off air equalizes, or-somewhat equalizes, the pressure'on both sides of the now preformed plastic sheet 13' and therefore allows the female mold "17 8 to be withdrawn fromthe preformed film 13 by movement of the shaft 240 in a downward direction. The blowoff air prevents any further stretching of the film 13 as themold 178 is withdrawn therefrom.

Two cooling positions, positions 7 and 8, may be provided, at which the film and card can be cooled prior to being discharged from the apparatus. At these positionsa suitable cooling means, such as fan 190, is pro- .vided.

As the preformed card 20 whichis positioned in the clamps 108 reaches position 9, it is ready-to be discharged intofla suitable container to be packed for subsequent shipment. Positioned at the discharge end of the preforming apparatus are the cam surfaces 146-similar in function to cam surfaces 144. The cam surface 146 are arranged and spaced a predetermined distance from the hubs 136 and are substantially cylindrical in shape. The cam surfaces 146 extend around the sprocket hubs 136, as may be seen in FIGURE 8, thereby maintaining the lever arms 122 of the clamps 188 in a depressed or open position, as viewed in FIGURE 12, which results in the card 20' beingin a position to be removed from the clamping devices 108. In FIGURE 8 there is shown an inclined surface 192 and after the clamps 108 have been opened and rotated over the hubs 136, the cards 20 drop to the surface 192 and slide thereon under the pull of gravity.

7 This is best illustrated on the right hand side of FIGURE 8. The cards 20 therefore slide onto a belt and pulley arrangement 194 and 196, part of which is shown in FIG- URE 8, and are carried thereby to a convenient receptacle.

The reciprocating action of the female mold 178 and the ratchet type or step by step movement of the sprocket chains 110 and, consequently, the clamps 108 are synchronized and are driven by an electric motor 200 partial- ]y illustrated in FIGURE 8, having a rotatable shaft 202. The rotatable shaft 202 is connected through an electric clutch 203 to a gear box 204, the details of which form no part of this invention, which can be manipulated to control the speed of movement of the sprocket chains 110 and the frequency of the reciprocation of the female mold 178. The gear box 204 is suitably connected to a common shaft 208 mounted in the housing 206 and the common shaft 208 is rotated in response to the movement of shaft 202. The rotational speed of shaft 208 may be adjusted by means of the gear box 204. Mounted on opposite ends of the common shaft 208 are cams 210 and 212, respectively. Cams 210 and 212 may be suitably attached to the common shaft 208 by any convenient means. Cam follower arm 216 rides on cam 212 at one end thereof and the other end of follower arm 216 is secured to shaft 240. Cam follower arm 216 is pivotably attached to the arm 218 which, in turn, is pivotably attached to housing 206 at portion 217 thereof by any convenient means. Attached to the common shaft 208 at the end opposite from cam 212 is cam 210. Cam 210 may be attached to the common shaft 208 in any convenient manner. Riding on the cam 210 is the cam follower arm 222. Cam follower arm 222 is pivotably attached to arm 224, which, in turn, is pivotably attached to the housing 206 at portion 226 thereof by any convenient means.

Attached to the upper end of cam follower arm 222 is cam follower jaw 228 having a pair of teeth 230 formed therein. Rigidly attached to shaft 232 of interconnecting sprocket hubs 136 and rotatable therewith is the drive mechanism 234. Shaft 232 is mounted in a pair of bearing housings 103 attached to the frame 100 and is freely rotatable therein. Formed on the periphery of the drive mechanism 234 are a plurality of spaced slots 236. The slots 236 are spaced along the periphery of the drive mechanism 234 and are engageable by the teeth 230 of the cam follower jaw 228. The sprocket hubs 136 are driven in a clockwise direction, as viewed in FIGURE 8, through the drive mechanism 234, which in turn is driven by jaw 228 having teeth 230 formed thereon. The cam follower arm 222 is driven upwardly, as viewed in FIG- URE 8, on the power stroke inasmuch as the cam 210 exerts only a pushing force on the cam follower arm 222 and the teeth 230 of jaw 228 slide down and engage the advancing slots 236 on the downward movement of cam follower arm 222.

The preferred forms of cams 210 and 212, illustrated in the drawings, and specifically FIGURES 8 and 9, are adopted to reciprocate the female mold 178 one time to move the sprocket chains 110 one increment during each revolution of the common shaft 208, and to synchronize the movement of the female mold 178 and the sprocket chain 110 to insure the movement of card 16 into its molding position without interference from mold 178. To this end the cams are synchronized to place the female mold 178 below the path of travel of card 16' during its movement into its molding position. It can now be seen that there is a positive, accurate and precise relationship between the reciprocating movement of the female mold 178 and the incremental movement of the sprocket chains 110 and, consequently, the clamps 108.

This positive, accurate and precise relationship is further insured by the use of certain controls in connection with the electric clutch 203. It may occasionally happen that the heating conditions of the machine in conjunction with the adhesive characteristics of the plastic film being used will cause the female mold 178 to remain in its upper position during the downward portion of its cycle. The continuation of the cycle would cause the card 16' to contact the rear edge of the mold 178 and to be ripped from the clamps 108. This action is prevented by a pair of double pole switches 246 and 248 having each of their respective upper and lower poles connected in series to the power supply of the electric clutch 203. If the switches 246 and 248 are in phase, i.e. if the two switches are both in the upper or the lower position, power will be supplied to clutch 203 causing it to remain engaged and allowing the operating cycle to continue; if the switches 246 and 248 are out of phase, i.e. if one is in the lower position and one is in the upper position, then the clutch power circuit will be opened causing the clutch to become disengaged and the machine to stop.

The power circuit will be disconnected only if the mold 178 remains in its upper position during the downward portion of its cycle because the switches 246 and 248 detect the movement of cam 212 and of the cam follower 216 and disengage the electric clutch 203 only when the cam follower 216 is not in engagement with cam 212. To this purpose, one of the switches, switch 246, is actuated by the cam follower 216 and the other of the switches, switch 248, is actuated by the common drive shaft 208. If the cam follower 216 is following cam 212, both switches will simultaneously be placed in their lowermost position by the cam follower 212 and the common shaft 208 respectively as soon as the mold 178 clears the path of travel of card 16, and will simultaneously be placed in their uppermost position when the mold 178 is placed in molding position. The electric clutch 203 thus remains engaged during the cycle because the mold 178 and the cam 212, and, therefore, the switches 246 and 248 are in phase. However, if the mold 178 is out of phase with the drive shaft 208 by remaining in its uppermost position during the downward portion of its cycle, then the switches 246 and 248 will be out of phase because the switch 248 will be placed in its lowermost position by shaft 208 and switch 246 will remain in its uppermost position because the cam follower 216 has not dropped and forced switch 246 into its lowermost position. This action will immediately disengage the clutch 203 and cause the machine to stop, preventing damage to the machinery and to the cards 16'.

It is also possible to disengage the electric clutch 203 at any time during the cycle by means of an appropriate mechanism on the control panel. This action during the molding portion of the cycle will allow the dwell time on a particular carton in the mold to be lengthened without a consequent time increase in the remainder of the cycle. Thus the mold dwell time may be independent of the conveyor travel time or the cycle time by a timed disengagement of the clutch during the molding portion of the cycle.

After the cards 20' have been discharged from the above apparatus, they may be packed and shipped to the consumer for subsequent loading and final sealing, or they may be conveniently stored, or they may be immediately loaded on the premises and finally sealed.

Clopane P plastic film of a 2 mil thickness was utilized in one embodiment of the plastic film windowed apertured card 16. An infrared heating source was located in the housing 166 of the preforming apparatus. The infrared source comprised approximately 288 square inches of heat emitting surface and the temperature of the heat emitting surface was 760 F. The plastic film windowed apertured card 16' was spaced 1% inches from the heat emitting surface. The dwell time of the plastic film windowed apertured card 16' under the heat emitting surface was 4.8 seconds.

What has been described is what is believed to be the preferred embodiments of the invention. However, various modifications and alterations may be made without departing from the true spirit and scope of the invention, as defined in the appended claims.

What is claimed is'i 1. Apparatu's foii preforming an article of manufacture for use in the stretchable film-packaging of items,

said article of m'anufacttire'comprising an apertured board ape after items have been packaged therein and restoring heat applied, comprising aplurality of pairs of sprockets, 7

a pair ofassociated chains adapted to fit around said sprockets in a continuous beltto thereby provide a pair'ofcont-inuous'conveyorbelts,

a plurality of spaced -.,pairs ofpo sitio'ning clampsfor saidarticle of manufacture rigidly secured to said chains, one clamp adapted; to travel in association with*'one chain and the other clamp of the pair adapted to travel with the other chain. Each clamp of a pair traveling opposite to the other clamp of the pair but not attached thereto, said clamps being spring biased to a normally closed position and each of saidclariips having formed thereon a clamp opening lever which when activated ope ns said clamps, v

forming means for stretching said plastic material of said article of manufacture to a predetermined shape corresponding to the contour of the items to be packaged within said article of manufacture, said forming means comprising a reciprocating mold,

cavities in said mold having connected thereto a vacuum source for causing saidfplastic material of said articlelof manufacture to be stretched and to adhere to the surfaces of said cavities of said mold,

a plurality of camming surfaces positioned at opposite ends of said pairs of conveyor belts and spaced a predetermined distance from said conveyor belts such that said lever arms of; clamps positioned adjacentjsaid camming surfaces are in contact with said carnming surfaces and,are opened thereby,

heating means operably associated with said conveyor belts and positioned adjacehtfi thereto and capable of heating said plastic materialto its thermoplastic temperature range so that it may be preformed,

and drive means adapted to' interruptingly drive said conveyor belts and to drivesaid reciprocating mold such that a predetermined relationship exists between the movement of said conveyor belts and the re ciprocating of said mold,

said conveyor belts sequentially moving spaced pairs of clamps into operable association with said heating means, said forming means, and said plurality of camming surfaces.

2. The apparatus of claim 1; in which air cooling means is associated with said conveyor belts and is positioned adjacent thereto, and is capable of cooling said plastic material,

and said conveyor belts sequentiallymove said spaced pairs of clamps into operable association with said cooling means.

3. Apparatus for preforrning an article of manufacture for use in the stretchable film-packaging of items, comiii 10 a plurality of ca'm'ming surfaces po'sitioned atopposite ends or said conveyor and spaced a predetermined distance from said conveyor such that saidlever arms positioned *on said clamps adjacentgsaid 'camming surfaces engage said c'a'mrningsurfaces and pivot in response to's'aid engagements to open'sa'id normally closed clamps at 'oppo'sifte ends 'o'fsaidconveyor belt, a reciprocating "female mold having' 'cavitie's formed therein of a predetermined configuration, said mold having a vacuumf-source attached "thereto 5 ces'si'tosaidcavities,

for said conveyor and saidreciprocating Lp i I Y a common than having positioned thereon a Pair of Cam's, I" 2: at! 1 My; one "of "said cams associated-and connected to said reciprocating mold by a plurality of connector arms, the other of said cams being connected to a means for providing an interrupted movement, said means: for providing an interrupted movement connected to said conveyor is interru'ptingly driven by said drive means,

said movement of said conveyor and said movement of said female mold having a predetermined relationship,

heating means operably associated with and positioned adjacent said conveyor,

said drive rrieans causing said plurality 'of spaced positioning clamps to be sequentially driven into an operable relationship with said heating means and said female'mold.

4. The apparatus of claim 3 in which cooling means is operably associated with and positioned adjacent said conveyor,

and said drive means causes said plurality of spaced positioning clamps to be sequentially driven into operableirelationship with said cooling means.

5. Apparatus for preforming an article of manufacture, said article of manufacture comprising an apertured sheet having a thermo-stretchable, thermo-sealable plastic material adhered to said apertured sheet, said article of manufacture ''capable of being preformed and will tend to return to its original shape after restoring heat has been appliedjthereto comprising:

a conveyor comprising a plurality of sprockets, a pair of associated link chains, each adapted to fit around bne of said sprockets to form a continuous belt, plurality of positioning clamps arranged in spaced pairs and rigidly attached to corresponding ones of said pair of chains and adapted to rigidly position and clamp said article of manufacture, said clamps in each pair being unconnected with the other one in the pair but arranged to travel one across from the other as the said chains move, heating means positioned in a cooperating relationship with said conveyor, forming means positioned adjacent said conveyor and said heating means, said forming means comprising a reciprocating mold, drive means for interruptingly driving said conveyor and for reciprocating said mold such that the movement of said conveyor and the reciprocating movement of said mold have a predetermined relationship,

said conveyor being sequentially driven into operable relationship with said heating means and said forming means, whereby said article of manufacture is preformed to a predetermined shape corresponding to the item to be packaged and said article of manufacture will remain in said stretched shape until said items to be packaged thereby have been packed therein and restoring heat applied.

6. The apparatus of claim 5 in which air cooling means is positioned in cooperating relationship with said conveyor, 7

and said conveyor is sequentially driven into operable relationship with said cooling means.

7. The apparatus of claim 5 in which I control means are provided for stopping said drive means from driving said conveyor,

said control means being operable by said drive means and said mold, and in which 7 said mold is moved from the path of said conveyor before said conveyor is sequentially driven into operational relationship with said forming means, and

said control means stops the movement of said conveyor if said mold does not move from the path of said conveyor in response to, said drive means.

References Cited by the Examiner UNITED STATES PATENTS -Wells 53388 Stokes et al. 1856 Ullin 198179 X Lewi 53-177 X Rohdin 53184 X Zimmerman 18-56 Brugger 53373 X Dewoskin, 53,l77- X Swezey 53-184 GRANVILLE Y. CUSTER, JR., Primary Examiner.

TRAVIS S. MCGEHEE, Examiner. 

1. APPARATUS FOR PERFORMING AN ARTICLE OF MANUFACTURE FOR USE IN THE STRETCHABLE FILM-PACKAGING OF ITEMS, SAID ARTICLE OF MANUFACTURE COMPRISING AN APERTURED BOARD HAVING A THERMO-STRETCHABLE, THERMO-SEALABLE PLASTIC MATERIAL ADHERED THERETO COVERING AT LEAST SAID APERTURE IN SAID BOARD, SAID ARTICLE OF MANUFACTURE CAPABLE OF BEING PERFORMED AND WHICH WILL TEND TO RETURN TO ITS ORIGINAL SHAPE AFTER ITEMS HAVE BEEN PACKAGED THEREIN AND RESTORING HEAT APPLIED, COMPRISING A PLURALITY OF PAIRS OF SPROCKETS, A PAIR OF ASSOCIATED CHAINS ADAPTED TO FIT AROUND SAID SPROCKETS IN A CONTINUOUS BELT TO THEREBY PROVIDE A PAIR OF CONTINUOUS CONVEYOR BELTS, A PLURALITY OF SPACED PAIRS OF POSITIONING CLAMPS FOR SAID ARTICLE OF MANUFACTURE RIGIDLY SECURED TO SAID CHAINS, ONE CLAMP ADAPTED TO TRAVEL IN ASSOCIATION WITH ONE CHAIN AND THE OTHER CLAMP OF THE PAIR ADAPTED TO TRAVEL WITH THE OTHER CHAIN. EACH CLAMP OF A PAIR TRAVELING OPPOSITE TO THE OTHER CLAMP OF THE PAIR BUT NOT ATTACHED THERETO, SAID CLAMPS BEING SPRING BIASED TO A NORMALLY CLOSED POSITION AND EACH OF SAID CLAMPS HAVING FORMED THEREON A CLAMP OPENING LEVEL WHICH WHEN ACTIVATED OPENS SAID CLAMPS, FORMING MEANS FOR STRETCHING SAID PLASTIC MATERIAL OF SAID ARTICLE OF MANUFACTURE TO A PREDETERMINED SHAPE CORRESPONDING TO THE CONTOUR OF THE ITEMS TO BE PACKAGED WITHIN SAID ARTICLE OF MANUFACTURE, SAID FORMING MEANS COMPRISING A RECIPROCATING MOLD, CAVITIES IN SAID MOLD HAVING CONNECTED THERETO A VACUUM SOURCE FOR CAUSING SAID PLASTIC MATERIAL OF SAID ARTICLE OF MANUFACTURE TO BE STRETCHED AND TO ADHERE TO THE SURFACES OF SAID CAVITIES OF SAID MOLD, A PLURALITY OF CAMMING SURFACES POSITIONED AT OPPOSITE ENDS OF SAID PAIRS OF CONVEYOR BELTS AND SPACED A PREDETERMINED DISTANCE FROM SAID CONVEYOR BELTS SUCH THAT SAID LEVER ARMS OF CLAMPS POSITIONED ADJACENT SAID CAMMING SURFACVES ARE IN CONTACT WITH SAID CAMMING SURFACES AND ARE OPENING THEREBY, HEATING MEANS OPERATIVELY ASSOCIATED WITH SAID CONVEYOR BELTS AND POSITIONED ADJACENT THERETO AND CAPABLE OF HEATING SAID PLASTIC MATERIAL TO ITS THERMOPLASTIC TEMPERATURE RANGE SO THAT IT MAY BE PERFORMED, AND DRIVE MEANS ADAPTED TO INTERRUPTINGLY DRIVE SAID CONVEYOR BELTS AND TO DRIVE SAID RECIPROCATING MOLD SUCH THAT A PREDETERMINED RELATIONSHIP EXISTS BETWEEN THE MOVEMENT OF SAID CONVEYOR BELTS AND THE RECIPROCATING OF SAID MOLD, SAID CONVEYOR BELTS SEQUENTIALLY MOVING SPACED PAIRS OF CLAMPS INTO OPERABLE ASSOCIATION WITH SAID HEATING MEANS, SAID FORMING MEANS, AND SAID PLURALITY OF CAMMING SURFACES. 